If you know proper water survival techniques such as making flotation devices out of your clothes then being out there for a night is not a huge deal for a young healthy person. After that you start running in to dehydration issues.

From this day to the ending of the world,
But we in it shall be rememberèd—
We few, we happy few, we band of brothers;
For he to-day that sheds his blood with me
Shall be my brother